The effect of ciprofloxacin on oral contraceptive steroid treatments.

The effect of ciprofloxacin, a new broad-spectrum quinolone derivative, on concomitant oral contraceptive steroids has been studied in a double-blind cross-over placebo-controlled randomized trial. Ten healthy women using long-term oral contraceptive steroids received either ciprofloxacin 500 mg BID or placebo during two consecutive cycles. Therapy was continued for seven days from the first day of contraceptive treatment. FSH, LH and oestradiol blood levels were repeatedly determined to monitor contraceptive steroid efficacy. A seven-day treatment with ciprofloxacin did not affect steroid treatment outcome and appears to be safe in women using this contraceptive method.